A database is a collection of logically related data arranged in a predetermined format, such as in tables that contain rows and columns. To access the content of a table in the database, queries according to a standard database query language (such as the Structured Query Language or SQL) are submitted to the database. A query can also be issued to insert new entries into a table of a database (such as to insert a row into the table), modify the content of the table, or to delete entries from the table. Examples of SQL statements include INSERT, SELECT, UPDATE, and DELETE.
In a relatively large database system, there can be a relatively large number of concurrently submitted database queries that are to be processed by the database system to produce results. When processing large numbers of queries, the resources of the database system can experience heavy workloads. If the workloads are not efficiently handled, then users of the database system may experience delays in obtaining results for queries.